Δ-4-cyclogeranic acid and process of making same.



UNITED STATES A CORPORATION OF GERMANY...

PATENT oFFiIoE GEORG MERLING, OF FRANKFORT-ON-THE-M-AIN, AND ALADAR SKITA, F HOCHST-ON-THE-MAIN. GERMANY; ASSIGNORS TO FARBwERKn'vo M, MEISTER, Lucius & BRUNING, OF HOCHST-ON-THE-MAIN, GERMANY,

47-4-CYCLOGERANIC ACID mp PROCESS OF MAKING SAME",

Specification of Letters Patent.

Patented. Nov. 28, 1905.

Application filed August 31, 1906. Serial No. 276.620- 7 To all whom it may concern fessor of chemistry, a citizen of the Empire of Germany, residing at Frankfort-on the- Main, and ALADAR SKITA, Ph. D, chemist, a

citizen of'the Empire of Austria-Hungary,'residing'at Hochst-on-the-Main, Germany, have invented certain new and useful Improvements in the Manufacture of L-Oyclogeranic Acid,

10 of which the followingis a specification.

lsophoronecarbox lic ester,

o c on,

H which readily loses one molecular proportion of hydrogen chlorid and becomes monochlorodehydro- 2:4-cyclogeranic ester,

The monochlorodehydro- 2,4-cyclogeranic acid produced by saponification of this latter ester can be further converted by reducing Be it known ,that we, GEORG MERLING, pro-- agentsinto -A-cyclogeranic acid,

on, on,

are introduced by degrees while cooling with ice and stirring one hundred parts of powdered phosphorus pentachlorid. The latter passes for the most part into solution without evolution of a considerable q'uanity of hydrogen chlorid. The liquid becomes brown.

When the flask has been removed from the ice, there begins at once without appreciable rise of temperature a lively evolution of hydrogen chlorid. As soon as this diminishes the solution is gently warmed on the waterbath, while the vessel is vigorously rotated until the evolution of hydrogen chlorid, which is now violent, abates.

oil, which is contaminated by a small proportion of a solid substance of unknown nature consisting of microscopic needles. the oil may be freed by being. heated for a short time with .a small proportion of alcoholic potash. The yield of the ester is about eighty per cent. ofthat calculated.

The pure monochlorodehydro- -2,4-cyclogeranic ester is a colorless and odorless mo bile oil which boils at 108 centigrade under Finally, for complet ing the reaction the mass is heated for a short time in the boilingwater bath. The loss of' From this six millimeters pressure. It reduces ammoniacal silver solution in the cold and absorbs oxygen rapidly in air, hydrogen chlorid being eliminated. In closed vessels from which the air has been displaced by carbon dioxid it remains unchanged. When heated with alcoholic potash in absence of air, the freshlydistilled ester loses no trace of hydrogen chlorid, but is smoothly saponified into monoehlorodehydro- Q, t-cyclogeranic acid, which crystallizes from ethyl acetate or benzene in large lustrous colorless prisms and is oxidized in air as easily as is its ester.

11. Reduction of monoc/dm'odeltydro- -2, .t-cyclogemm'c acid to A -.4-cy0l0gerani0 acid. One part of the ester is saponified by being boiled for several hours with one part of caustic potash and two parts of alcohol. The mixture is then diluted with twenty parts of alcohol. The clear solution is heated to the boiling-point, and one and one-half parts of sodium are introduced by degrees. When the metal has disappeared, the colorless solution, which is very turbid owing to the separated finely-divided salt, is diluted with water and the alcohol is driven over with steam. By adding dilute sulfuric acid to the cooled alkaline solution the t-cyclogeranie acid is precipitated as a yellowish oil, immediately solidifying to beautiful crystals. The acid can be isolated by draining and washing or by shaking out with ether. By asingle recrystallization from hot ethyl acetate or ligroin it is obtained completely pure. The yield is nearly quantitative. The L-cyclogeranic acid is easily soluble in alcohol, ether, benzene, or acetone. From hot ethyl acetate or ligroin it crystallizes on cooling in large well-formed glassy prisms which melt at 103 centigrade. The solution of the acid in sodium carbonate decolorizes permanganate immediately in the cold. Under six millimeters pressure it boils at 123.5 centigrade undecomposed. The distillate, clear as water, immediately solidifies on cooling to a hard crystalline mass. The acid absorbs exactly two atomic proportions of bromin. The dibromo-addition product is distinguished from the dibromodihydro-alpha-cyclogeranic acid of Tiemann by its instability in that it loses onemolecular proportion of hydrogen bromid even at ordinary temperature, becoming a monobromot-cyclogeranie acid.

The ethyl ester of t-eyclogeranic acid (09H15.GO0G2H5) obtained by boiling the alcoholic solution of the potassium salt with ethyl iodid is a colorless agreeably-smelling oil, boiling at 94: centigrade under six millimeters pressure. The same ester is produced by the reduction of the monochlorodehydro- 2,4:cyclogeranic ester with sodium and alcohol, but together with a considerable proportion of the carbinol, (GnHaCH-gOHJ owing to simultaneous reduction of the COOCszIIt group.

The anilid of -4cycloge1*anic acid (Cilia. CONHCGHE) forms colorless needles, which easily dissolve in hot alcohol, but are diiiicultly soluble in cold alcohol. It melts at 158 centigrade.

In a similar mannerphosphorus pentabromid reacts with isophorone-carboxylic ester, yet less smoothly than phosphorus pentachlorid, and from the product of reaction may be obtained similarly as described above i-cyclogeranic acid. The red notion of monochloro or monobromo dehydro- -2,4Lcyclogeranic acid or its esters may occur, besides with sodium and alhocol, also in an acid solution for instance, with glacial acetic acid and zincdust or with sodium amalgam in dilute acetic alcoholic solution; but the yields of t-hydrogeranic acid or its ester are essentially inferior to those of the process hereinbefore described.

, The t-cyclogeranic acid serves for the manufacture of irone.

Having now described our invention, what we claim is 1. The process herein described for the manufacture of l-cyclogeranic acid, which consists in producing monochlorodehyd10- -52, t-cyclogeranie ester from isophorone carboxylic ester and phosphorus pentachlorid and in treating this ester with reducing agents.

2. The process herein described for the manufacture of l-cyclogeranic acid, which consists in producing monochlorodehydro- -Q, t-cyclogeranic ester from isophorone carboxylic ester and phosphorus pentachlorid and in treating this ester after saponilication with reducing agents.

3. As new product, the t-cyclogeranic acid being readily soluble in alcohol, ether, benzene and acetone, crystallizing from hot ethyl acetate or ligroin on cooling in large, well-formed, glassy prisms which melt at 103 centigrade; under six millimeters pressure it boils at 123 centigrade undecomposed; the distillate, clear as water, immediately solidifies on cooling to a hard crystalline mass.

In testimony that we claim the foregoing as our invention we have signed our names in presence of two subscribing witnesses.

GEORG MERLING. ALADAR SKITA.

Witnesses:

JEAN GRUND, CARL GRUND. 

